A. Field of the Invention
This invention relates to polyamide fibers containing as an antiozonant one or more poly(copper phosphinates) of the formula ##STR1## where R is --H, --CH.sub.3, --CH.sub.2 CH.sub.3, --CH.sub.2 CH.sub.2 CO.sub.2 H or ##STR2## R' is ##STR3## n is a whole number greater than one, with the proviso that R and R' may be joined to form the radical ##STR4## (i.e., in ##STR5## or ##STR6## The term "polyCuP" when used hereinafter means a compound of the above formula. Fibers of the invention, when dyed with disperse dyes, have significantly improved resistance to ozone fading when compared to corresponding fibers dyed with disperse dyes from which the polyCuP has been omitted. The term "ozone fading", as used herein, means color fading of dyed fiber resulting from the dyed fiber being exposed to ozone. The term "fiber" as used herein means spun or continuous filament yarn, or a monofilament.
B. Description of the Prior Art
Polyamide fibers, especially those dyed with disperse dyes, exhibit considerable fading of color when exposed to ozone at high humidities, i.e. exhibit ozone fading. Such conditions are encountered along the Gulf Coastal regions and in areas of high atmospheric pollution. Ozone fading is more severe in open structured polyamides (e.g. nylon 6), wax-filled polyamides and copolyamides.
It has been suggested in the prior art to use certain tertiary amines as a coating material (U.S. Pat. No. 3,892,525) or certain organic phosphites as an additive (U.S. Pat. No. 3,844,713) for the purpose of reducing ozone fading of polyamide fibers. These techniques however have certain drawbacks, for example, the extra step required for the application of a coating material is usually inconvenient and costly. On the other hand, a relatively large amount of the organic phosphite additive is required to effectively reduce ozone fading in polyamides (i.e. 0.1 to 8%).
Poly (metal phosphinates) have been described in the chemical and patent literature. Pennsalt Chemical Corp. (now Pennwalt Corp.) Technical Data (i.e. bulletin) entitled "Metal Phosphinate Polymers" was published prior to the subject invention. In this bulletin certain zinc and chromium phosphinates are described as being useful as UV stabilizers for polyvinyl chloride and as antistatic coatings, alkali-resistant fibers and coatings, heat distortion improvers for epoxy resins, accelerators for epoxy resins, propellant modifiers and high-temperature coatings.
U.S. 3,275,574 relates to various poly (metal phosphinates), such as, where the metal is chromium, iron, ruthenium, europium and ytterbium. The particular phosphinates are described as having high-temperature stability and being useful as fabricated articles or coatings where high temperatures are encountered.
U.S. Pat. No. 3,538,136 relates to poly (aluminum phosphinates) which are described as being useful as surface coatings, heat shields, etc. in applications requiring heat stability at elevated temperatures.
U.S. Pat. No. 3,654,189 describes a method for producing poly (metal phosphinates) wherein a solution of a dihydrocarbon phosphinic acid in acetic anhydride is heated under reflux with a hydrous polyvalent metal nitrate (s). The nitrate may be a hydrated nitrate of a Group II-A, I-B, II-B, III-B, IV-B, V-B, VI-B, VII-B, VIII or a rare earth metal, such as cerium, of the periodic table. The phosphinates are disclosed as being useful as pigments in water-base latex or acrylic resin paints in amounts ranging from 15 to 40% as well as in a variety of other applications.
Japanese patent 49-130462 relates to flame-resistant molding resins containing from 0.1 to 40 wt. % and, preferably, 2 to 10 wt. % of a poly (metal phosphinate), where the metal may be Ca, Sr, Ba, Zn, B, Be, Cd, Hg, Co, Ni, Cu, Ag, Au, Pd, Cr, Mn, Ti, V, Fe, Co, Pd, Si, Sn, Rh, etc.
U.S. Pat. No. 4,049,612 relates to poly (metal phosphinates) as smoke-retardants for polyvinyl halide resin.